Search

We aimed to objectively compare the effects of wearing newer, higher-ranked football helmets (HRank) vs. wearing older, lower-ranked helmets (LRank) on pre- to post-season alterations to neuroimaging-derived metrics of athletes' white matter. Fifty-four high-school athletes wore an HRank helmet, and 62 athletes wore an LRank helmet during their competitive football season and completed pre- and post-season diffusion tensor imaging (DTI). Longitudinal within- and between-group DTI metrics [fractional anisotropy (FA) and mean/axial/radial diffusivity (MD, AD, RD)] were analyzed using tract-based spatial statistics. The LRank helmet group exhibited significant pre- to post-season reductions in MD, AD, and RD, the HRank helmet group displayed significant pre- to post-season increases in FA, and both groups showed significant pre- to post-season increases in AD (p's < .05 [corrected]). Between-group analyses revealed the pre- to post-season increase in AD was significantly less for athletes wearing HRank compared to LRank (p < .05 [corrected]). These data provide in vivo evidence that wearing an HRank helmet may be efficacious for preserving white matter from head impact exposure during high school football. Future prospective longitudinal investigations with complimentary imaging and behavioral outcomes are warranted to corroborate these initial in vivo findings.

Patellofemoral pain (PFP) is defined as retro- or peri-patellar knee pain without a clear structural abnormality. Unfortunately, many current treatment approaches fail to provide long-term pain relief, potentially due to an incomplete understanding of pain-disrupted sensorimotor dysfunction within the central nervous system. The purposes of this study were to evaluate brain functional connectivity in participants with and without PFP, and to determine the relationship between altered brain functional connectivity in association with patient-reported outcomes. Young female patients with PFP (n = 15; 14.3 ± 3.2 years) completed resting-state functional magnetic resonance imaging (rs-fMRI) and patient-reported outcome measures. Each patient with PFP was matched with two controls (n = 30, 15.5 ± 1.4 years) who also completed identical rs-fMRI testing. Six bilateral seeds important for pain and sensorimotor control were created, and seed-to-voxel analyses were conducted to compare functional connectivity between the two groups, as well as to determine the relationship between connectivity alterations and patient-reported outcomes. Relative to controls, patients with PFP exhibited altered functional connectivity between regions important for pain, psychological functioning, and sensorimotor control, and the connectivity alterations were related to perceived disability, dysfunction, and kinesiophobia. The present results support emergent evidence that PFP is not localized to structural knee dysfunction, but may actually be resultant to altered central neural processes. Clinical significance: These data provide potential neuro-therapeutic targets for novel therapies aimed to reorganize neural processes, improve neuromuscular function, and restore an active pain-free lifestyle in young females with PFP.

Few studies have investigated the effect of external loads secured inferior to the center of mass (COM) on postural control and motor performance in younger and older adults. In the present study, we investigated the effect of systematically increased external loads secured inferior to the COM on young (N = 15, age [years]: M = 26.67, SD= 3.45) and older adults' (N = 15, age [years]: M = 67.4, SD= 7.69) center of pressure displacement and velocity, and also dart throwing performance in four different load conditions: 1) no load (control condition), 2) loading with 5% of body mass, 3) loading with 10% of body mass, and 4) loading with 20% of body mass. Overall, older adults had higher COP displacement and velocity in both anterior/posterior (AP) and Medio-lateral (ML) directions and poorer dart throwing scores than younger adults. Despite no significant difference in dart throwing performance for the different load conditions within each age group, loading with 10% and 20% of body mass reduced AP COP displacement relative to control for both study groups, with 20% body mass also reducing AP COP velocity relative to control for both study groups. In conclusion the present findings reveal that external loads secured inferior to older and younger adults' COM may enhance postural control without compromising motor performance. The findings were discussed in the context of fall-prevention and athletic performance.

Current best practices to direct recovery after sports-related concussion (SRC) typically require asymptomatic presentation at both rest and during a graduated exercise progression, and cognitive performance resolution. However, this standard of care results in a significantly elevated risk for musculoskeletal (MSK) injury after return-to-sport (RTS). The elevated risk is likely secondary to, in part, residual neurophysiological and dual-task motor stability deficits that remain despite RTS. These deficits present as a loss of autonomous control of gait and posture and an increased need for cognition for motor stability. Thus, the incorporation of strategies that can enhance motor stability and restore autonomous control of gait and posture during SRC recovery and RTS progression may facilitate a reduction of the elevated risk of secondary MSK injury. We provide a theoretical framework for the application of motor learning principles to restore autonomous gait and postural stability after SRC via incorporation, or targeted manipulation, of external focus, enhanced expectations, autonomy support, practice schedule variability, and dual-task strategies during rehabilitation and RTS training.

To quantify the effects of an externally worn collar device for mitigating the influence of repetitive head impacts on alterations to diffusion tensor imaging (DTI) metrics of white matter. Fifteen female high-school soccer athletes (age: 14.00–16.98 yrs) completed pre- and post-season DTI over two consecutive years, including measures of diffusivity, changes in which may be associated with brain dysfunction. The collar was worn during year 1 (Yr1) but not during year 2 (Yr2). Athlete exposures (AEs) and head impact exposure were recorded over the competitive seasons. There were no significant differences in AEs or head impact exposures between Yr1 and Yr2 (P > 0.05). In Yr2, there was significant pre- to post-season mean diffusivity and/or axial diffusivity reduction in multiple WM regions (corrected P

Youth athletes are ideal candidates for novel therapeutic motor learning interventions that leverage the plasticity of the central nervous system to promote desirable biomechanical adaptions. We summarize the empirical data supporting the three pillars of the Optimizing Performance Through Intrinsic Motivation and Attention for Learning (OPTIMAL) theory of motor learning and expand on potential neurophysiologic mechanisms that will support enhanced movement mechanics in youth to optimize prevention programs for reduced injury risk, injury rehabilitation, exercise performance, and play (Prevention Rehabilitation Exercise Play; PREP). Specifically, we highlight the role of motivational factors to promote the release of dopamine that could accelerate motor performance and learning adaptations. Further, we detail the potential for an external focus of attention to shift attentional allocation and increase brain activity in regions important for sensorimotor integration to facilitate primary motor cortex efficiency. This manuscript serves to provide the most current data in support of the application of OPTIMAL PREP training strategies of the future.

BACKGROUND: Emergent linkages between musculoskeletal injury and the nervous system have increased interest to evaluate brain activity during functional movements associated with injury risk. Functional magnetic resonance imaging (fMRI) is a sophisticated modality that can be used to study brain activity during functional sensorimotor control tasks. However, technical limitations have precluded the precise quantification of lower-extremity joint kinematics during active brain scanning. The purpose of this study was to determine the validity of a new, MRI-compatible motion tracking system relative to a traditional multi-camera 3D motion capture system for measuring lower extremity joint kinematics. METHODS: Fifteen subjects (9 females, 6 males) performed knee flexion-extension and leg press movements against guided resistance while laying supine. Motion tracking data were collected simultaneously using the MRI-compatible and traditional multi-camera 3D motion systems. Participants’ sagittal and frontal plane knee angles were calculated from data acquired by both multi-camera systems. Resultant range of angular movement in both measurement planes were compared between both systems. Instrument agreement was assessed using Bland-Altman plots and intraclass correlation coefficients (ICC). RESULTS: The system demonstrated excellent validity in the sagittal plane (ICCs>0.99) and good to excellent validity in the frontal plane (0.84

There are numerous physical, social, and psychological benefits of exercise, sport and play for youth athletes. However, dynamic activities come with a risk of injury that has yet to be abated, warranting novel therapeutics to promote injury-resistance and to keep an active lifestyle throughout the lifespan. The purpose of the present manuscript was to summarize the extant literature and potential connecting framework regarding youth brain development and neuroplasticity associated with musculoskeletal injury. This review provides the foundation for our proposed framework that utilizes the OPTIMAL (Optimizing Performance Through Intrinsic Motivation and Attention for Learning) theory of motor learning to elicit desirable biomechanical adaptations to support injury prevention (injury risk reduction), rehabilitation strategies, and exercise performance for youth physical activity and play across all facets of sport (Prevention Rehabilitation Exercise Play; PREP). We conclude that both young male and females are ripe for OPTIMAL PREP strategies that promote desirable movement mechanics by leveraging a unique time window for which their heightened state of central nervous system plasticity is capable of enhanced adaptation through novel therapeutic interventions.

Youth may be particularly responsive to motor learning training strategies that support injury-resistant movement mechanics in youth for prevention programs that reduce injury risk, injury rehabilitation, exercise performance, and play more generally (Optimizing Performance Through Intrinsic Motivation and Attention for Learning Prevention Rehabilitation Exercise Play; OPTIMAL PREP) One purpose of the present manuscript was to provide clinical applications and tangible examples of how to implement the proposed techniques derived from OPTIMAL theory into PREP strategies for youth. A secondary purpose was to review recent advances in technology that support the clinical application of OPTIMAL PREP strategies without extensive resources/programming knowledge to promote evidence-driven tools that will support practitioner feedback delivery. The majority of examples provided are within the context of anterior cruciate ligament (ACL) injury rehabilitation, but we emphasize the potential for OPTIMAL PREP strategies to be applied to a range of populations and training scenarios that will promote injury resistance and keep youth active and healthy.

Background: Characterization of, and evaluation of strategies to mitigate, the effects of sub-concussive impacts (SCI) on brain structure and function are crucial to understanding potential long-te...

ACL ruptures are rapidly increasing.1 ACL injuries can have a profound impact on an athlete’s physical and psychological functioning, and sporting career. Current standard of care following ACL injury is neuromuscular rehabilitation to help athletes regain motor skills. Optimising how rehabilitation is delivered has the potential to further enhance motor relearning and reduce the risk of secondary knee injuries.2 ACL injury rehabilitation programmes aiming to reduce secondary injury risk often involve explicit learning strategies to improve biomechanics and increase neuromuscular control.3 Athletes are mostly instructed to consciously control movements using internally focused, verbal cues that prescribe desired movement patterns (eg, ‘do not bring your knees over your toes’ during squatting). Only with sustained practice does explicit learning result in consistent, fluent, and automatic, motor performance. Recently, practitioners have been encouraged to minimise explicit learning during ACL injury rehabilitation, and use implicit learning interventions such as external focus cues.2 We contend that implicit interventions are not a panacea, and that explicit interventions remain important in ACL injury rehabilitation. We discuss key individual characteristics and contextual constraints that warrant the use of explicit interventions. ### Why would implicit learning be beneficial to ACL rehabilitation? The theoretical advantage of implicit learning interventions is that athletes reach automaticity earlier in the learning process. Accordingly, implicit …

OBJECTIVE Youth athletes are believed to be more susceptible to white matter (WM) degradation resulting from head impact exposure relative to high school (HS) athletes; this hypothesis has not been objectively tested. The purpose of this study was to determine preseason to postseason changes in WM integrity from repetitive head impacts for youth football (YFB) players compared with HS football players during a competitive football season. DESIGN Prospective cohort. SETTING One season of YFB (grades 7 and 8) and varsity HS football (grades 10-12). PATIENTS OR OTHER PARTICIPANTS Twelve YFB (13.08 ± 0.64 years) and 21 HS (17.5 ± 0.78 years) athletes. INTERVENTIONS Participants completed 2 magnetic resonance imaging sessions: preseason and postseason. Head impact exposure was recorded during practice and games using a helmet-mounted accelerometer. MAIN OUTCOME MEASURES Tract-based spatial statistics were used to evaluate group differences in preseason to postseason changes in diffusion tensor imaging, including fractional anisotropy and mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD). RESULTS The HS group exhibited significant preseason to postseason reductions in MD, AD, and RD (P < 0.05, corrected) in widespread WM areas. Significant WM reductions for the YFB group were only observed for AD (P < 0.05, corrected), but was more limited in extent compared with HS. CONCLUSIONS Significant preseason to postseason AD reduction was found in both YFB and HS groups after one season of competitive play. Our results did not confirm recent speculation that younger children are more susceptible to the deleterious effects of repetitive head impacts compared with their older counterparts.

Context: Existing anterior cruciate ligament (ACL) injury prevention programs have failed to reverse the high rate of ACL injuries in adolescent female athletes. Objective: This investigation attempts to overcome factors that limit efficacy with existing injury prevention programs through the use of a novel, objective, and real-time interactive visual feedback system designed to reduce the biomechanical risk factors associated with ACL injuries. Design: Cross-over study. Setting: Medical center laboratory. Participants: A total of 20 females (age = 19.7 [1.34] y; height = 1.74 [0.09] m; weight = 72.16 [12.45] kg) participated in this study. Methods: Participants performed sets of 10 bodyweight squats in each of 8 training blocks (ie, 4 real-time and 4 control blocks) and 3 testing blocks for a total of 110 squats. Feedback conditions were blocked and counterbalanced with half of participants randomly assigned to receive the real-time feedback block first and half receiving the control (sham) feedback first. Results: Heat map analysis revealed that during interaction with the real-time feedback, squat performance measured in terms of key biomechanical parameters was improved compared with performance when participants squatted with the sham stimulus. Conclusions: This study demonstrates that the interactive feedback system guided participants to significantly improve movement biomechanics during performance of a body weight squat, which is a fundamental exercise for a longer term ACL injury risk reduction intervention. A longer training and testing period is necessary to investigate the efficacy of this feedback approach to effect long-term adaptations in the biomechanical risk profile of athletes.

This prospective longitudinal trial aimed to 1) determine the role of head impact exposure on behavioral/cognitive outcomes, and 2) assess the protective effect(s) of a jugular vein compression (JVC) collar on behavioral/cognitive outcomes following one season of high-school football. Participants included 284 male high-school football players aged 13-18 years enrolled from seven midwestern high-schools. Schools were allocated to the JVC collar intervention(four teams, 140 players) or non-collar/no intervention control (three teams, 144 players) condition. Head impact exposure was measured throughout the season using CSx accelerometers. Outcome measures included post season parent and adolescent report on Strengths and Weaknesses of ADHD Symptoms and Normal Behavior Scale (SWAN) and Post-Concussion Symptom Inventory (PCSI), as well as adolescent performance on Attention Network Task (ANT), digital Trail Making Task (dTMT), and Cued Switching task. No significant effect of head impact exposure or JVC collar use on post-season SWAN or PCSI scores or performance on dTMT and Cued Switching task were noted. There was no effect of head impact exposure on ANT performance; however, the JVC collar group had greater post-season Alerting network scores than the non-collar group (p=.026, d=.22). Findings provide preliminary evidence that the JVC collar may provide some protection to the alerting attention system. These findings should be interpreted cautiously as a greater understanding of the long-term sequalae of head impact exposure and the role of cumulative head impact exposure behavioral/cognitive outcomes is required.

Sports-related concussion (SRC) can exert serious acute and long-term consequences on brain microstructure, function, and behavioral outcomes. We aimed to quantify the alterations in white matter (WM) microstructure and global network organization, and the decrements in behavioral and cognitive outcomes from pre-season to post-concussion in youth athletes who experienced SRC. We also aimed to evaluate whether wearing a jugular compression neck collar, a device designed to mitigate brain "slosh" injury, would mitigate the pre-season to post-concussion alterations in neuroimaging, behavioral, and cognitive outcomes. A total of 488 high school football and soccer athletes (14-18 years old) were prospectively enrolled and assigned to the non-collar group (

BACKGROUND AND PURPOSE: The purpose of this study was to assess the consistency of a novel MR safe lower extremity motor control neuroimaging paradigm to elicit reliable sensorimotor region brain activity. METHOD: Participants completed multiple sets of unilateral leg presses combining ankle, knee, and hip extension and flexion movements against resistance at a pace of 1.2 Hz while lying supine in a 3T MRI scanner. Regions of Interest (ROI) consisted of regions primarily involved in lower extremity motor control (right and left primary motor cortex, primary somatosensory cortex, pre-motor cortex, secondary somatosensory cortex, basal ganglia, and the cerebellum). RESULTS: The group analysis based on mixed effects paired samples t-test revealed no differences for brain activity between sessions (p>0.05). Intraclass correlation coefficients in the sensorimotor regions were good to excellent for average percent signal change (0.621 to 0.918) and Z-score (0.697 to 0.883), with the exception of the left secondary somatosensory cortex percent signal change (0.165). CONCLUSIONS: These results indicate that a loaded lower extremity force production and attenuation task that simulates the range of motion of squatting, stepping, and landing from a jump is reliable for longitudinal neuroimaging applications and support the use of this paradigm in further studies examining therapeutic interventions and changes in dynamic lower extremity motor function.

Objectives (1) To determine the effects of concussion-related motor impairments at different task complexities in isolation and with a cognitive dual-task and (2) to determine if self-reported balance deficits after concussion are associated with gait, quiet stance, or cognitive dual-task impairments. Design Cross-sectional study. Setting Sports medicine clinic. Participants Adolescent athletes clinically diagnosed with a sport-related concussion and those without concussion. Forty-nine patients with concussion (mean age=14.9±1.9y; 51% female; tested 7.0±3.0d postinjury) and 65 control participants (mean age=14.9±1.6y; 52% female) completed the study (N=114). Interventions Athletes with concussion completed a single-task and dual-task standing and walking protocol within 14 days of injury and were compared to those without concussion. Main Outcome Measures Outcome measures included gait speed, quiet stance (root mean square [RMS] coronal/sagittal plane sway), and cognitive performance (accuracy). Dual-task costs were calculated as the percentage change between single-task and dual-task conditions. Participants with concussion were then stratified by those who did and did not report subjective balance problems at the time of testing and compared using objective balance and gait metrics. Results The concussion group walked slower during dual-task gait than controls (0.83±0.17 m/s vs 0.92±0.15 m/s; Cohen’s d=0.53). Dual-task quiet stance RMS sway values were similar for concussion and control groups in coronal (1.20±0.52 m/s-2 vs 1.26±0.65 m/s-2; d=0.09) and sagittal (0.56±0.24 m/s-2 vs 0.73±0.44 m/s-2; d=0.20) movement planes. The concussion participants with subjectively-reported balance problems had significantly greater walking speed dual-task costs than concussion participants without self-reported balance problems (-25±10% vs -19±9%; P=.02). Conclusions Following concussion, adolescents demonstrate slower gait speeds, but similar quiet stance values relative to those without concussion. The study results indicate that tasks requiring greater motor coordination may elicit greater alterations following a concussion.

Introduction Special Weapons and Tactics (SWAT) personnel who practice breaching with blast exposure are at risk for blast-related head trauma. We aimed to investigate the impact of low-level blast exposure on underlying white matter (WM) microstructure based on diffusion tensor imaging (DTI) and neurite orientation and density imaging (NODDI) in SWAT personnel before and after breacher training. Diffusion tensor imaging is an advanced MRI technique sensitive to underlying WM alterations. NODDI is a novel MRI technique emerged recently that acquires diffusion weighted data from multiple shells modeling for different compartments in the microstructural environment in the brain. We also aimed to evaluate the effect of a jugular vein compression collar device in mitigating the alteration of the diffusion properties in the WM as well as its role as a moderator on the association between the diffusion property changes and the blast exposure. Materials and Methods Twenty-one SWAT personnel (10 non-collar and 11 collar) completed the breacher training and underwent MRI at both baseline and after blast exposure. Diffusion weighted data were acquired with two shells (b = 1,000, 2,000 s/mm2) on 3T Phillips scanners. Diffusion tensor imaging metrices, including fractional anisotropy, mean, axial, and radial diffusivity, and NODDI metrics, including neurite density index (NDI), isotropic volume fraction (fiso), and orientation dispersion index, were calculated. Tract-based spatial statistics was used in the voxel-wise statistical analysis. Post hoc analyses were performed for the quantification of the pre- to post-blast exposure diffusion percentage change in the WM regions with significant group difference and for the assessment of the interaction of the relationship between blast exposure and diffusion alteration. Results The non-collar group exhibited significant pre- to post-blast increase in NDI (corrected P Conclusions Our data provided initial evidence of the impact of blast exposure on WM diffusion alteration based on both DTI and NODDI. The mitigating effect of WM diffusivity changes and the moderating effect of collar wearing suggest that the device may serve as a promising solution to protect WM against blast exposure.

The purpose of this clinical trial was to examine whether internal jugular vein compression (JVC)-using an externally worn neck collar-modulated the relationships between differential head impact exposure levels and pre- to postseason changes in diffusion tensor imaging (DTI)-derived diffusivity and anisotropy metrics of white matter following a season of American tackle football. Male high-school athletes (n = 284) were prospectively assigned to a non-collar group or a collar group. Magnetic resonance imaging data were collected from participants pre- and postseason and head impact exposure was monitored by accelerometers during every practice and game throughout the competitive season. Athletes' accumulated head impact exposure was systematically thresholded based on the frequency of impacts of progressively higher magnitudes (10 g intervals between 20 to 150 g) and modeled with pre- to postseason changes in DTI measures of white matter as a function of JVC neck collar wear. The findings revealed that the JVC neck collar modulated the relationships between greater high-magnitude head impact exposure (110 to 140 g) and longitudinal changes to white matter, with each group showing associations that varied in directionality. Results also revealed that the JVC neck collar group partially preserved longitudinal changes in DTI metrics. Collectively, these data indicate that a JVC neck collar can provide a mechanistic response to the diffusion and anisotropic properties of brain white matter following the highly diverse exposure to repetitive head impacts in American tackle football. Clinicaltrials.gov: NCT# 04068883.

Cumulative exposure to head impacts during contact sports can elicit potentially deleterious brain white matter alterations in young athletes. Head impact exposure is commonly quantified using wearable sensors; however, these sensors tend to overestimate the number of true head impacts that occur and may obfuscate potential relationships with longitudinal brain changes. The purpose of this study was to examine whether data-driven filtering of head impact exposure using machine learning classification could produce more accurate quantification of exposure and whether this would reveal more pronounced relationships with longitudinal brain changes. Season-long head impact exposure was recorded for 22 female high school soccer athletes and filtered using three methods—threshold-based, heuristic filtering, and machine learning (ML) classification. The accuracy of each method was determined using simultaneous video recording of a subset of the sensor-recorded impacts, which was used to confirm which sensor-recorded impacts corresponded with true head impacts and the ability of each method to detect the true impacts. Each filtered dataset was then associated with the athletes’ pre- and post-season MRI brain scans to reveal longitudinal white matter changes. The threshold-based, heuristic, and ML approaches achieved 22.0% accuracy, 44.6%, and 83.5% accuracy, respectively. ML classification also revealed significant longitudinal brain white matter changes, with negative relationships observed between head impact exposure and reductions in mean and axial diffusivity and a positive relationship observed between exposure and fractional anisotropy (all p

To compare cross-recurrence quantification analysis measurements obtained during gait between adolescents who sustained a diagnosed concussion within 14 days of assessment and healthy adolescents.Cross-sectional study.Youth athletes with concussion (n = 43; mean ± SD age, 14.4 ± 2.3 years; 56% female; tested median, 7 days post concussion) and healthy controls (n = 38; age, 14.9 ± 2.0 years; 55% female) completed a single-task and dual-task gait protocol while wearing a set of inertial sensors. We used cross-recurrence quantification analysis techniques to quantify the similarity between accelerations obtained from the sensor on the dorsum of each foot. Four outcome variables were compared between groups: percent determinism, average diagonal-line length, laminarity, and trapping time.Athletes with concussion had significantly higher percent determinism, laminarity, and trapping time than the control group in single-task and dual-task conditions (Higher percent determinism, laminarity, and trapping time among athletes with concussion suggest that concussion may be associated with a more stuck and predictable gait pattern. These altered movement patterns may be one reason for underlying slower gait speeds that have been observed following concussion.

Background: Cumulative exposure to repetitive sub-concussive head impacts in contact sports may have deleterious effects on brain function, even in the absence of acute symptoms. Moreover, anatomical and biomechanical factors may predispose female athletes to higher risk compared to males. At present, there is no effective injury prevention strategy to protect female athletes from sports-related head impact. Hypothesis/Purpose: (1). We aimed to use resting-state fMRI to investigate the effect of a full season of competitive soccer on brain functional network integrity in female high school athletes. (2). We also aimed to evaluate the efficacy of a jugular vein compression neck collar device, designed to mitigate potential injury by reducing the brain slosh effect. Methods: A total of 125 high school female soccer athletes were included in this study. These athletes were assigned randomly to a non-collar (n=55, age=16.06±1.06 yrs) or collar group (n=70, 15.81±0.95 yrs) before the season started. High resolution 3D T1-weighted images and resting-state fMRI data were collected prospectively at pre-season and again at post-season. Data processing and analysis were conducted in the MATLAB-based programs Statistical Parametric Mapping (SPM12) and Connectivity Toolbox (Conn). Functional connectivity was computed between each pair of 105 anatomically delineated regions of interest (ROI). Network Based Statistics were applied to detect coherent patterns of altered connectivity from pre- to post-season. Results: The non-collar group showed a significant pattern of altered connectivity (p-FWE = 0.047) spanning 60% of ROIs (63/105) and 1.7% of ROI-ROI connections (94/5,460). 65 of the 94 altered connections were weakened from pre-to-post season and tended to occur in the right hemisphere. 29 of the 94 altered connections were strengthened from pre-to-post season and tended to involve regions in the occipital lobe. The collar group did not show any statistically significant change (p-FWE = 0.223). Conclusion: The results of this study indicate that exposure to repetitive sub-concussive head impacts during a single season of competitive female soccer induces changes in brain functional connectivity. The observed increases and decreases of functional connectivity strength comprising the pattern of altered connectivity are congruent with a heterogeneous response to insult wherein some connections are reduced in strength due to neuronal damage and other “detour” connections are strengthened to preserve network function. Comparatively, the absence of alterations in the collar group suggest that the jugular vein compression collar may have generated a potentially protective effect to preserve brain functional network integrity during exposure to head impacts. [Figure: see text]

Background: Patellofemoral pain (PFP) is a chronic knee condition that affects over 1 in 4 physically-active girls. PFP symptomology contributes to dysfunctional motor control and heightened kinesiophobia (i.e., fear of pain/movement). Both chronic pain and kinesiophobia induce substantial changes throughout the central nervous system (CNS) in many populations who experience pain (e.g., low back pain), but such relationships have not been explored in pediatric patients with PFP. As current treatment approaches for PFP generally fail to provide complete symptom mitigation, identifying the mechanisms by which kinesiophobia exacerbate PFP and disrupt the CNS could provide mechanistic neural pathways to guide novel, brain-based treatments for pain relief. Hypothesis/Purpose: The purpose of this study was to determine the relationship between kinesiophobia and brain functional activation during a knee motor control task in pediatric patients with PFP. Methods: Girls clinically diagnosed with PFP ( n = 15; 14.3 ± 3.2 yrs) were positioned supine in a 3 Tesla magnetic resonance imaging (MRI) scanner and completed a series of unilateral 45° knee extension/flexion movements during functional MRI (fMRI). Patients completed this open kinetic chain movement at a frequency of 1.2 Hz (Figure 1.1). Patients also completed the Tampa Scale of Kinesiophobia (TSK; scores range from 0 – 68, with scores greater than 37 indicating high kinesiophobia). Correlation analyses were performed to determine whether kinesiophobia was associated with brain activity during the motor task. Statistical corrections were made to account for multiple, voxel-wise comparisons. Results: Study patients exhibited high kinesiophobia, with a mean TSK score of 38.27 (SD = 5.79). Neuroimaging analyses revealed that greater kinesiophobia was directly associated with increased brain activity in a cluster located within the occipital pole/cuneus, supracalcarine cortex, and intracalcarine cortex (p < .001, z-max = 4.30; Figure 1). Conclusion: The results revealed that the degree of kinesiophobia was related to the magnitude of visual-related brain activity for knee motor control. As perceived fear of movement increases, patients with PFP may recruit additional visual resources to compensate for pain-disrupted somatosensory processing. Future interventions that promote sensorimotor engagement and reduce visual feedback for motor control (i.e., dynamic movements with occluded vision) may be beneficial to reorganize neural processes, decrease kinesiophobia, and restore an active lifestyle in young girls with PFP. Tables/Figures: [Figure: see text]

Background: Anterior cruciate ligament (ACL) injuries are debilitating for athletes. While numerous motor and biomechanical deficits contribute to the inciting ACL injury mechanism, the limited knowledge about the underlying neural drivers of these deficits has impeded intervention development to reduce ACL injury rates. A prospective investigation using functional magnetic resonance imaging (fMRI) in female soccer players revealed decreased connectivity between the primary somatosensory cortex and cerebellum for athletes that went on to ACL injury athletes compared to their healthy teammates. Although information about inter-region connectivity patterns is informative, this finding does elucidate the individual, intra-region brain activity that may be further underlie ACL injury mechanisms. Hypothesis/Purpose: The purpose of this study was to prospectively investigate the intra-region regularity of the blood oxygen-level dependent (BOLD) signal activity in 25 knee-related regions of interests (ROI) between athletes who sustained an ACL injury and matched controls. Methods: Adolescent female soccer athletes were evaluated using fMRI to capture resting-state brain connectivity prior to their competitive season. Two of these athletes (16.0±0yrs, 169.0±2.8cm, 60.1±8.3kg) later experienced an ACL injury and were matched to eight uninjured teammates (15.9±0.8yrs, 164.0±4.9cm, 58.3±7.6kg). Standard fMRI data processing was used to determine resting-state BOLD signal activity in 25 knee-related ROIs. Sample entropy (SampEn) was then used to quantify the regularity of each individual ROI. A lower SampEn value indicates a ROI’s BOLD signal activity was more regular (predictable) and a higher value indicates a signal’s activity was more irregular (unpredictable). T-tests—with a Bonferroni correction for the familywise error rate ( p < .002)—were used to compare SampEn values between both groups for all 25 ROIs. Results: ACL injured athletes ( M = 0.35±0.01) exhibited higher SampEn values in the left primary motor cortex than matched, uninjured athletes ( M = 0.29±0.02; t(8)=4.62, p=.0017, d=3.65). Conclusion: Athletes who sustained an ACL injury exhibited less regularity in BOLD signal activity of the left primary motor cortex. As the primary motor cortex serves as the final destination in the brain before efferent information is sent to the spinal cord to initiate movement, decreased BOLD signal regularity in this region may alter such cortical-spinal transmission. Considering ACL injuries often occur during unpredictable environments, irregular activity of motor cortex activity may dampen an athlete’s ability to sustain a safe knee position. These findings may help to guide development of brain-driven biofeedback training to promote adaptive neuroplasticity that ‘pushes’ the motor cortex towards more regular activity. [Figure: see text]

Prospective evidence indicates that functional biomechanics and brain connectivity may predispose an athlete to an anterior cruciate ligament injury, revealing novel neural linkages for targeted neuromuscular training interventions. The purpose of this study was to determine the efficacy of a real-time biofeedback system for altering knee biomechanics and brain functional connectivity. Seventeen healthy, young, physically active female athletes completed 6 weeks of augmented neuromuscular training (aNMT) utilizing real-time, interactive visual biofeedback and 13 served as untrained controls. A drop vertical jump and resting state functional magnetic resonance imaging were separately completed at pre- and posttest time points to assess sensorimotor adaptation. The aNMT group had a significant reduction in peak knee abduction moment (pKAM) compared to controls (p = .03, d = 0.71). The aNMT group also exhibited a significant increase in functional connectivity between the right supplementary motor area and the left thalamus (p = .0473 after false discovery rate correction). Greater percent change in pKAM was also related to increased connectivity between the right cerebellum and right thalamus for the aNMT group (p = .0292 after false discovery rate correction, r2 = .62). No significant changes were observed for the controls (ps > .05). Our data provide preliminary evidence of potential neural mechanisms for aNMT-induced motor adaptations that reduce injury risk. Future research is warranted to understand the role of neuromuscular training alone and how each component of aNMT influences biomechanics and functional connectivity.

Anterior cruciate ligament (ACL) injuries are physically and emotionally debilitating for athletes, while motor and biomechanical deficits that contribute to ACL injury have been identified, limited knowledge about the relationship between the central nervous system (CNS) and biomechanical patterns of motion has impeded approaches to optimize ACL injury risk reduction strategies. In the current study it was hypothesized that high-risk athletes would exhibit altered temporal dynamics in their resting state electrocortical activity when compared to low-risk athletes. Thirty-eight female athletes performed a drop vertical jump (DVJ) to assess their biomechanical risk factors related to an ACL injury. The athletes' electrocortical activity was also recorded during resting state in the same visit as the DVJ assessment. Athletes were divided into low- and high-risk groups based on their performance of the DVJ. Recurrence quantification analysis was used to quantify the temporal dynamics of two frequency bands previously shown to relate to sensorimotor and attentional control. Results revealed that high-risk participants showed more deterministic electrocortical behavior than the low-risk group in the frontal theta and central/parietal alpha-2 frequency bands. The more deterministic resting state electrocortical dynamics for the high-risk group may reflect maladaptive neural behavior—excessively stable deterministic patterning that makes transitioning among functional task-specific networks more difficult—related to attentional control and sensorimotor processing neural regions.

Background:Female athletes are at an increased risk of developing patellofemoral pain (PFP) relative to male athletes. The unique effects of maturation may compound that risk.Hypothesis/Purpose:The purpose was to evaluate the neuromuscular control mechanisms that are adaptive to pubertal maturation and determine their relative contribution to PFP development. It was hypothesized that aberrant landing mechanics (reduced sagittal-plane and increased frontal- and transverse-plane kinematics and kinetics) would be associated with an increased risk for PFP.Study Design:Cohort study; Level of evidence, 2.Methods:There were 506 high school female athletes who completed a detailed medical history, the Anterior Knee Pain Scale, and a knee examination for the diagnosis of PFP and attended follow-up appointments. Athletes performed a drop vertical jump task instrumented with force plates, and biomechanical measures generated from standard 3-dimensional biomechanical analyses were used to classify participants into high- or low-risk knee and hip landing profiles for the development of PFP. The biomechanical measures used in the knee landing profile included sagittal-plane knee range of motion, peak knee abduction angle, peak knee abduction moment, and peak-to-peak transverse-plane knee moment. The biomechanical measures used in the hip landing profile included sagittal-plane hip range of motion, peak hip extensor moment, peak abductor moment, and peak hip rotator moment. Testing was conducted at sport-specific preseason appointments over the course of 2 years, and changes in pubertal status, landing profile, and PFP development were documented.Results:Female athletes with high-risk hip landing profiles experienced increased hip flexion and decreased abductor, rotator, and extensor moments. Participants with high-risk hip landing profiles who transitioned to postpubertal status at follow-up had higher odds (odds ratio, 2.1 [95% CI, 1.1-4.0]; P = .02) of moving to a low-risk hip landing profile compared with those who had not reached postpubertal status at follow-up. Participants with high-risk knee landing profiles experienced decreased knee flexion and increased knee abduction, external abductor, and external rotator moments. Pubertal maturation was not associated with a change in the high-risk knee landing profile at follow-up.Conclusion:The progression from prepubertal to postpubertal status may have a protective effect on high-risk hip mechanics but no similar adaptations in high-risk knee mechanics during maturation. These data indicate that before puberty, maladaptive hip mechanics may contribute to PFP, while aberrant knee mechanics associated with PFP are sustained throughout the maturational process in young female athletes.

Exposure to explosive blasts places one at risk for traumatic brain injury, especially for special weapons and tactics (SWAT) and military personnel, who may be repeatedly exposed to blasts. In the current study, the effectiveness of a jugular vein compression collar to prevent alterations in resting-state electrocortical activity following a single-SWAT breacher training session was investigated. SWAT team personnel were randomly assigned to wear a compression collar during breacher training and resting state electroencephalography (EEG) was measured within 2 days prior to and two after breacher training. It was hypothesized that significant changes in brain dynamics-indicative of possible underlying neurodegenerative processes-would follow blast exposure for those who did not wear the collar, with ameliorated changes for the collar-wearing group. Using recurrence quantification analysis (RQA) it was found that participants who did not wear the collar displayed longer periods of laminar electrocortical behavior (as indexed by RQA's vertical max line measure) after breacher training. It is proposed that the blast wave exposure for the no-collar group may have reduced the number of pathways, via axonal disruption-for electrical transmission-resulting in the EEG signals becoming trapped in laminar states for longer periods of time. Longer laminar states have been associated with other electrocortical pathologies, such as seizure, and may be important for understanding head trauma and recovery.

This study examined the training effect of attentional focus (external focus, internal focus, or no focus instructions) on a dynamic balance task. Participants completed baseline balance testing, seven consecutive days of dynamic balance board training, and retention testing 24 hours after the last session. The novel finding of this study was the presence of a training effect on balance control when adopting an external focus relative to an internal focus or no focus instructions. Further, we report the unique observation that more patterned behavior was adopted regardless of the focus instructions. These findings provide insight into how instructions can be altered to enhance human balance control and complement the constrained-action hypothesis.

Background: Anterior cruciate ligament (ACL) injuries predominantly occur via non-contact mechanisms, secondary to motor coordination errors resulting in aberrant frontal plane knee loads that exceed the thresholds of ligament integrity. However, central nervous system processing underlying high injury-risk motor coordination errors remain unknown, limiting the optimization of current injury reduction strategies. Purpose: To evaluate the relationships between brain activity during motor tasks with injury-risk loading during a drop vertical jump. Methods: Thirty female high school soccer players (16.10 ± 0.87 years, 165.10 ± 4.64 cm, 63.43 ± 8.80 kg) were evaluated with 3D biomechanics during a standardized drop vertical jump from a 30 cm box and peak knee abduction moment was extracted as the injury-risk variable of interest. A neuroimaging session to capture neural activity (via blood-oxygen-level-dependent signal) was then completed which consisted of 4 blocks of 30 seconds of repeated bilateral leg press action paced to a metronome beat of 1.2 Hz with 30 seconds rest between blocks. Knee abduction moment was evaluated relative to neural activity to identify potential neural contributors to injury-risk. Results: There was a direct relationship between increased landing knee abduction moment and increased neural activation within regions corresponding to the lingual gyrus, intracalcarine cortex, posterior cingulate cortex, and precuneus (r2= 0.68, p corrected < .05, z max > 3.1; Table 1 & Figure 1). Conclusion: Elevated activity in regions that integrate sensory, spatial, and attentional information may contribute to elevated frontal plane knee loads during landing. Interestingly, a similar activation pattern related to high-risk landing mechanics has been found in those following injury, indicating that predisposing factors to injury may be accentuated by injury or that modern rehabilitation does not recover prospective neural control deficits. These data uncover a potentially novel brain marker that could guide the discovery of neural-therapeutic targets that reduce injury risk beyond current prevention methods. [Table: see text][Figure: see text]

Background: Aberrant frontal and sagittal plane knee motor control biomechanics contribute to increased anterior cruciate ligament (ACL) injury risk. Emergent data further indicates alterations in brain function may underlie ACL injury high risk biomechanics and primary injury. However, technical limitations have limited our ability to assess direct linkages between maladaptive biomechanics and brain function. Hypothesis/Purpose: (1) Increased frontal plane knee range of motion would associate with altered brain activity in regions important for sensorimotor control and (2) increased sagittal plane knee motor control timing error would associate with altered activity in sensorimotor control brain regions. Methods: Eighteen female high-school basketball and volleyball players (14.7 ± 1.4 years, 169.5 ± 7 cm, 65.8 ± 20.5 kg) underwent brain functional magnetic resonance imaging (fMRI) while performing a bilateral, combined hip, knee, and ankle flexion/extension movements against resistance (i.e., leg press) Figure 1(a). The participants completed this task to a reference beat of 1.2 Hz during four movement blocks of 30 seconds each interleaved in between 5 rest blocks of 30 seconds each. Concurrent frontal and sagittal plane range of motion (ROM) kinematics were measured using an MRI-compatible single camera motion capture system. Results: Increased frontal plane ROM was associated with increased brain activity in one cluster extending over the occipital fusiform gyrus and lingual gyrus ( p = .003, z > 3.1). Increased sagittal plane motor control timing error was associated with increased brain activity in multiple clusters extending over the occipital cortex (lingual gyrus), frontal cortex, and anterior cingulate cortex ( p < .001, z > 3.1); see Figure 1 (b). Conclusion: The associations of increased knee frontal plane ROM and sagittal plane timing error with increased activity in regions that integrate visuospatial information may be indicative of an increased propensity for knee injury biomechanics that are, in part, driven by reduced spatial awareness and an inability to adequately control knee abduction motion. Increased activation in these regions during movement tasks may underlie an impaired ability to control movements (i.e., less neural efficiency), leading to compromised knee positions during more complex sports scenarios. Increased activity in regions important for cognition/attention associating with motor control timing error further indicates a neurologically inefficient motor control strategy. [Figure: see text]

Background: Anterior cruciate ligament (ACL) injury is secondary to a multifactorial etiology encompassing anatomical, biological, mechanical, and neurological factors. The nature of the injury being primarily due to non-contact mechanics further implicates neural control as a key injury-risk factor, though it has received considerably less study. Purpose: To determine the contribution of neural activity to injury-risk mechanics in ecological sport-specific VR landing scenarios. Methods: Ten female high-school soccer players (15.5±0.85 years; 165.0±6.09 cm; 59.1±11.84 kg) completed a neuroimaging session to capture neural activity during a bilateral leg press and a 3D biomechanics session performing a header within a VR soccer scenario. The bilateral leg press involved four 30 s blocks of repeated bilateral leg presses paced to a metronome beat of 1.2 Hz with 30 s rest between blocks. The VR soccer scenario simulated a corner-kick, requiring the participant to jump and head a virtual soccer ball into a virtual goal (Figure 1A-E). Initial contact and peak knee flexion and abduction angles were extracted during the landing from the header as injury-risk variables of interest and were correlated with neural activity. Results: Evidenced in Table 1 and Figure 1 (bottom row), increased initial contact abduction, increased peak abduction, and decreased peak flexion were associated with increased sensory, visual-spatial, and cerebellar activity (r2= 0.42-0.57, p corrected < .05, z max > 3.1, table & figure 1). Decreased initial contact flexion was associated with increased frontal cortex activity (r2= 0.68, p corrected < .05, z max > 3.1). Conclusion: Reduced neural efficiency (increased activation) of key regions that integrate proprioceptive, visual-spatial, and neurocognitive activity for motor control may influence injury-risk mechanics in sport. The regions found to increase in activity in relation to higher injury-risk mechanics are typically activated to assist with spatial navigation, environmental interaction, and precise motor control. The requirement for athletes to increase their activity for more basic knee motor control may result in fewer neural resources available to maintain knee joint alignment, allocate environmental attention, and handle increased motor coordination demands. These data indicate that strategies to enhance efficiency of visual-spatial and cognitive-motor control during high demand sporting activities is warranted to improve ACL injury-risk reduction. [Figure: see text][Table: see text]

Background: Patellofemoral pain (PFP) is a chronic knee condition that inhibits movement quality and can cascade into kinesiophobia (i.e., fear of pain/movement). Despite its high prevalence in adolescent girls, PFP etiology has remained elusive, potentially due to an incomplete understanding of how pain, motor control, and kinesiophobia interact with central nervous system (CNS) functioning. Discovering linkages between motor control, kinesiophobia, and the CNS for patients with PFP could provide novel opportunities to refine neural therapeutic strategies for enhanced, personalized treatment approaches. Hypothesis/Purpose: To identify neural markers of kinesiophobia in pediatric patients with PFP. Methods: Adolescent girls clinically diagnosed with PFP ( n = 14; 14.3 ± 3.2 yrs) were positioned supine in a magnetic resonance imaging (MRI) scanner. A modified Clarke’s test (patellofemoral grind test) was administered to the left knee of patients during brain functional MRI (fMRI) acquisition. The experimenter placed a hand at the superior patellar border applying intermittent distal pressure while the patient contracted her quadriceps. Patients also completed a quadriceps contraction test without application of external pressure (control). Kinesiophobia was measured using the Tampa Scale of Kinesiophobia. fMRI analyses compared brain activation between the two tasks, and correlation analyses were performed to assess relationships between task-induced brain activity and kinesiophobia. Statistical corrections were made to account for multiple, voxel-wise comparisons. Results: Evidenced in Table 1 and Figure 1A, neuroimaging analyses revealed distinct bidirectional activation during the Clarke’s test compared to the control (all p corrected < .05, all z max > 3.1). Table 1 and Figure 1B further highlight that greater kinesiophobia was associated with increased brain activity during the Clarke’s test in two clusters (both p corrected < .05, both z max > 3.1), but no relationships between kinesiophobia and brain activity during the control test were observed (all p corrected > .05, all z max < 3.1). Conclusion: The current results indicate that the Clarke’s test induced differential pain-related brain activity relative to the control (e.g., paracingulate gyrus). The patients’ degree of kinesiophobia was also related to brain activity in regions important for sensorimotor control, attention, and pain. Collectively, these data indicate that PFP may be due to alterations in nociceptive processing throughout the CNS, providing novel complementary pathways for targeted restoration of patellofemoral joint dysfunction. Future research should consider combined mechanistic pain profiling, sensorimotor, psychometric, and CNS assessments to identify patients most susceptible to kinesiophobia to refine treatment approaches that work towards a goal of disease prevention. Tables/Figures: [Figure: see text][Table: see text]

BACKGROUND: To better understand the neural drivers of aberrant motor control, methods are needed to identify whole brain neural correlates of isolated joints during multi-joint lower-extremity coordinated movements. This investigation aimed to identify the neural correlates of knee kinematics during a unilateral leg press task. NEW METHOD: The current study utilized an MRI-compatible motion capture system in conjunction with a lower extremity unilateral leg press task during fMRI. Knee joint kinematics and brain activity were collected concurrently and averaged range of motion were modeled as covariates to determine the neural substrates of knee out-of-plane (frontal) and in-plane (sagittal) range of motion. RESULTS: Increased out-of-plane (frontal) range of motion was associated with altered brain activity in regions important for attention, sensorimotor control, and sensorimotor integration (z >3.1, p < .05), but no such correlates were found with in-plane (sagittal) range of motion (z >3.1, p > .05). COMPARISON WITH EXISTING METHOD(S): Previous studies have either presented overall brain activation only, or utilized biomechanical data collected outside MRI in a standard biomechanics lab for identifying single-joint neural correlates. CONCLUSIONS: The study shows promise for the MRI-compatible system to capture lower-extremity biomechanical data collected concurrently during fMRI, and the present data identified potentially unique neural drivers of aberrant biomechanics. Future research can adopt these methods for patient populations with CNS-related movement disorders to identify single-joint kinematic neural correlates that may adjunctively supplement brain-body therapeutic approaches.

This study examined the effect of 24h of sleep deprivation on cognitive performance and assessed the effect of acute exercise on cognitive performance following sleep deprivation. Young, active, healthy adults (n=24, 14 males) were randomized to control (age=24.7±3.7years, BMI=27.2±7.0) or exercise (age=25.3±3.3years, BMI=25.6±5.1) groups. Cognitive testing included a 5-min psychomotor vigilance task (PVT), three memory tasks with increasing cognitive load, and performance of the PVT a second time. On morning one, cognitive testing followed a typical night's sleep. Following 24-h of sustained wakefulness, cognitive testing was conducted again prior to and after the acute intervention. Participants in the exercise condition performed low-intensity cycling (∼40%HRR) for 15-min and those in the control condition sat quietly on the bike for 15-min. t-Tests revealed sleep deprivation negatively affected performance on the PVT, but did not affect memory performance. Following the acute intervention, there were no cognitive performance differences between the exercise and rested conditions. We provide support for previous literature suggesting that during simple tasks, sleep deprivation has negative effects on cognitive performance. Importantly, in contrast to previous literature which has shown multiple bouts of exercise adding to cognitive detriment when combined with sleep deprivation, our results did not reveal any further detriments to cognitive performance from a single-bout of exercise following sleep deprivation.

Competitive sport participation, in contact and collision sports, exposes athletes to repetitive head impacts. Although these impacts do not always result in overt symptomology or a diagnosed "concussion," evidence indicates that cumulative repetitive impacts affect brain pathophysiology. The purpose of this study was to perform a systematic review of prospective, longitudinal trials evaluating repetitive head impact exposure on white matter (WM) microstructure in collision and contact sport athletes to inform clinical care and treatment strategies. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed to determine studies that met predetermined inclusion and exclusion criteria. Initially, 2498 abstracts were identified, and 20 studies were critically evaluated herein. The majority of studies demonstrated significant longitudinal changes in anisotropy and/or diffusivity metrics that were associated with the quantity and/or the magnitude of head impact exposure, highlighting the utility of diffusion tensor imaging (DTI) for measuring changes in WM microstructure. Our review also comments on study methodology and describes how age, sex, sport, and time between sport cessation and DTI measures contribute to divergent findings within the literature. Suggestions for future research are also provided to overcome previous study limitations and maximize our understanding of the role of repetitive head impact exposure on WM integrity and long-term neurological sequela.

Objective This study’s purpose was to utilize a prospective dataset to examine differences in functional brain connectivity in male high school athletes who suffered an anterior cruciate ligament (ACL) injury relative to their non-injured peers. Methods Sixty-two male high school football players were evaluated using functional magnetic resonance imaging prior to their competitive season to evaluate resting-state functional brain connectivity. Three athletes later experienced an ACL injury and were matched to 12 teammates who did not go on to sustain an ACL injury (controls) based on school, age, height, weight, and year in school. Twenty-five knee-motor regions of interest (ROIs) were created to identify differences in connectivity between the two groups. Between-subject F and t tests were used to identify significant ROI differences using a false discovery rate correction for multiple comparisons. Results There was significantly less connectivity between the left secondary somatosensory cortex and the left supplementary motor area (p = 0.025), right pre-motor cortex (p = 0.026), right supplementary motor area (p = 0.026), left primary somatosensory cortex (superior division; p = 0.026), left primary somatosensory cortex (inferior division; p = 0.026), and left primary motor cortex (p = 0.048) for the ACL-injured compared to the control subjects. No other ROI-to-ROI comparisons were significantly different between the groups (all p > 0.05). Conclusion Our preliminary data indicate a potential sensorimotor disruption for male football players who go on to experience an ACL injury. Future studies with larger sample sizes and complementary measures of neuromuscular control are needed to support these findings.

Falls in older adults are a public health challenge due to their influence on well-being and health-care costs. One way to address this challenge is to discover new methods to enhance postural control in older adults so they are better prepared to maintain an upright stance. Older and younger adults (N?=?32) performed a static balance task on a force plate with no instructions, internal focus instructions, or external focus instructions. Center of pressure displacement time series were analyzed using sample entropy and standard deviation. Only the external focus condition significantly increased postural control entropy, which was observed across both age groups. This study showed that an external focus of attention can be used to increase postural control entropy within a single session of testing.

Persistent gait alterations can occur after concussion and may underlie future musculoskeletal injury risk. We compared dual-task gait stability measures among adolescents who did/did not sustain a subsequent injury post-concussion, and uninjured controls. Forty-seven athletes completed a dual-task gait evaluation. One year later, they reported sport-related injuries and sport participation volumes. There were three groups: concussion participants who sustained a sport-related injury (n = 8, age =15.4 &plusmn, 3.5 years, 63% female), concussion participants who did not sustain a sport-related injury (n = 24, 14.0 &plusmn, 2.6 years, 46% female), and controls (n = 15, 14.2 &plusmn, 1.9 years, 53% female). Using cross-recurrence quantification, we quantified dual-task gait stability using diagonal line length, trapping time, percent determinism, and laminarity. The three groups reported similar levels of sports participation (11.8 &plusmn, 5.8 vs. 8.6 &plusmn, 4.4 vs. 10.9 &plusmn, 4.3 hours/week, p = 0.37). The concussion/subsequent injury group walked slower (0.76 &plusmn, 0.14 vs. 0.65 &plusmn, 0.13 m/s, p = 0.008) and demonstrated higher diagonal line length (0.67 &plusmn, 0.08 vs. 0.58 &plusmn, 0.05, p = 0.02) and trapping time (5.3 &plusmn, 1.5 vs. 3.8 &plusmn, 0.6, p = 0.006) than uninjured controls. Dual-task diagonal line length (hazard ratio =1.95, 95% CI = 1.05&ndash, 3.60), trapping time (hazard ratio = 1.66, 95% CI = 1.09&ndash, 2.52), and walking speed (hazard ratio = 0.01, 95% CI = 0.00&ndash, 0.51) were associated with subsequent injury. Dual-task gait stability measures can identify altered movement that persists despite clinical concussion recovery and is associated with future injury risk.

Independent Component Analysis-based Automatic Removal of Motion Artifacts (ICA-AROMA; Pruim et al., 2015) is a robust approach to remove brain activity related to head motion within functional magnetic resonance imaging (fMRI) datasets. However, ICA-AROMA requires command line implementation and customized code to batch process large datasets. We developed a cross-platform, open-source graphical user Interface for Batch processing fMRI datasets using ICA-AROMA (INFOBAR). INFOBAR allows a user to search directories, identify appropriate datasets, and batch execute ICA-AROMA. INFOBAR also has additional data processing options and visualization features to support all researchers interested in mitigating head motion artifact in post-processing using ICA-AROMA.

Postural sway is significantly affected by a mild traumatic brain injury, or concussion, and myriad methods have been developed to quantify the severity of concussion symptoms. The current manuscript quantifies postural sway—as measured by an inertial sensor—in youth athletes with concussion (n = 43, age = 14.4 ± 2.3 years, 56% female, tested median 7 days post-concussion) and healthy controls (n = 38, age = 14.9 ± 2.0 years, 55% female) during single-task and dual-task postural sway. A nonlinear analysis (i.e., recurrence quantification analysis [RQA]) and several common linear measures were used to quantify postural sway. Respectively, the two complementary types of analyses describe the structure and magnitude of postural sway. We hypothesized that participants who recently experienced a concussion would display differing postural sway dynamics (i.e., different in structure and magnitude) than control participants who had not experienced a concussion. Additionally, a logistic regression was performed to determine which combination of variables (nonlinear and linear) and task (single and dual) would best differentiate concussion and control participants. Significant differences between concussion and control participants were found in percent determinism, laminarity, and standard deviation of postural sway acceleration in both the single and the dual task. In the single task alone, mean diagonal line length and trapping time were additionally significantly different between groups. Moreover, the logistic regression model revealed that a mixture of linear and nonlinear measures across both single and dual tasks best classified concussed and non-concussed participants. Additionally, history of concussion was found to be a significant covariate in the model. These results extend past observations by demonstrating that a combination of posture sway tasks and measurements best differentiate participants with a concussion. These results highlight the need for future studies to replicate the findings in different populations and further determine which combinations of postural sway tasks and measurements best classify participants with concussions.

Background: Sports-related concussion is a significant public health problem which may result in exacerbated or prolonged neurologic deficits. A neck collar device has been developed to apply mild jugular vein compression, increasing intracranial blood volume, with the intent of reducing brain slosh and preventing damage to brain microstructure from head impact exposure. Hypothesis/Purpose: We aimed to quantify the alterations in white matter (WM) diffusion properties and network structural connectivity in high school athletes after sports-related concussion and to test the effect of a jugular vein compression collar device worn during the concussive event. Methods: 379 athletes (male American football and female Soccer) were included in this report. Of the 16693 total athlete exposures, 40 resulted in a diagnosed concussion and were included in these analyses. Prospective longitudinal MRI data were collected at pre-season and post-concussion: 20 athletes were in the non-collar group (12M, age =15.93±1.27yrs) and 20 athletes were in the non-collar group (16M, age=16.37±1.06yrs). DTI parameters, including fractional anisotropy (FA), and mean, axial and radial diffusivity (MD/AD/RD), were calculated to determine post-concussion alterations in WM diffusion properties. Graph analysis was utilized to quantify post-concussion changes in WM structural connectivity. Results: Diffusion property results revealed significant pre-season to post-concussion increases in MD, AD and RD within the non-collar group (p0.05). The pre-season to post-concussion MD, AD, or RD increase was significantly greater (pDiscussion & Conclusion: Results indicate that sports related concussion is associated with alterations in WM diffusion properties. The mean local efficiency of the network, a structural connectivity index reflecting network wiring redundancy and tolerance to brain injury, was also found to decrease after the concussion. Results indicate that wearing a neck collar device has the potential to limit these WM changes following a concussive event. Further studies are warranted to investigate the temporal progression of these changes for preventing long-term, neurologic squeala. [Figure: see text][Figure: see text]

Context: A limiting factor for reducing anterior cruciate ligament injury risk is ensuring that the movement adaptions made during the prevention program transfer to sport-specific activity. Virtual reality provides a mechanism to assess transferability, and neuroimaging provides a means to assay the neural processes allowing for such skill transfer. Objective: To determine the neural mechanisms for injury risk–reducing biomechanics transfer to sport after anterior cruciate ligament injury prevention training. Design: Cohort study. Setting: Research laboratory. Participants: Four healthy high school soccer athletes. Interventions: Participants completed augmented neuromuscular training utilizing real-time visual feedback. An unloaded knee extension task and a loaded leg press task were completed with neuroimaging before and after training. A virtual reality soccer-specific landing task was also competed following training to assess transfer of movement mechanics. Main Outcome Measures: Landing mechanics during the virtual reality soccer task and blood oxygen level–dependent signal change during neuroimaging. Results: Increased motor planning, sensory and visual region activity during unloaded knee extension and decreased motor cortex activity during loaded leg press were highly correlated with improvements in landing mechanics (decreased hip adduction and knee rotation). Conclusion: Changes in brain activity may underlie adaptation and transfer of injury risk–reducing movement mechanics to sport activity. Clinicians may be able to target these specific brain processes with adjunctive therapy to facilitate intervention improvements transferring to sport.

Objectives We aimed to present a unique prospective neurological dataset for participants who experienced an ACL injury. Design Prospective longitudinal case-control. Methods High school female soccer athletes were evaluated using functional magnetic resonance imaging to capture resting-state brain connectivity prior to their competitive season. Two of these athletes later experienced an ACL injury (ACLI). We matched these ACLI participants with eight teammates who did not go on to sustain an ACL injury (uninjured controls, Con) based on age, grade, sex, height, and weight to examine differences in preseason connectivity. Knee-motor regions of interest (ROIs) were created based on previously published data from which five specific areas were selected as seeds for analysis. Independent-samples t-tests with a false discovery rate correction for multiple comparisons determined differences in connectivity between the ACLI and Con. Results There was significantly greater connectivity between the left primary sensory cortex (a brain region responsible for proprioception) and the right posterior lobe of the cerebellum (a brain region responsible for balance and coordination) for the Con relative to ACLI, t (8) = 4.53, p = 0.03 (false discovery rate corrected). Conclusions These preliminary data indicate that those who do not later sustain an ACL injury exhibit a stronger functional connection between a cortical sensory-motor region and a cerebellar region responsible for balance and coordination. These findings may help to guide development of brain-driven biofeedback training that optimizes and promotes adaptive neuroplasticity to reduce motor coordination errors and injury risk.

Background/Study Context: Employing the stereotype content model and terror management theory, we examined whether stereotypes and feelings about persons with dementia vary depending on the type of dementia diagnosis and purported causes of the dementia.Participants were randomly assigned to read one of four vignettes that depicted a man who consulted his doctor because of memory problems. All vignettes described the same symptoms and diagnostic tests, but each of four groups read a different result: all tests normal (Normal); Alzheimer's disease (AD); Wernicke-Korsakoff Syndrome (WKS) associated with alcohol abuse; and chronic traumatic encephalopathy (CTE) associated with head injuries from playing football in high school and college. Measures included a word fragment completion task, a stereotype content scale, and an emotions scale.Results showed no differences in the number of death-related words generated in the word fragment completion task and no differences in assessment of competence across the four groups. Those in the Normal, AD, and CTE groups evaluated the man as warmer than those in the WKS group. Participants in the AD condition showed more empathy than those in the WKS group. There were no differences in pity or fear but the CTE condition produced more envy and admiration and the WKS condition produced more contempt.These results suggest that different forms of dementia elicit varying emotional and cognitive responses.

Context: Although the beneficial effects of using an external focus of attention are well documented in attainment and performance of movement execution, neural mechanisms underlying external focus’ benefits are mostly unknown. Objective: To assess brain function during a lower-extremity gross motor movement while manipulating an internal and external focus of attention. Design: Cross-over study. Setting: Neuroimaging center Participants: A total of 10 healthy subjects (5 males and 5 females) Intervention: Participants completed external and internal focus of attention unilateral left 45° knee extension/flexion movements at a rate of 1.2 Hz laying supine in a magnetic resonance imaging scanner for 4 blocks of 30 seconds interspersed with 30-second rest blocks. During the internal condition, participants were instructed to “squeeze their quadriceps.” During the external condition, participants were instructed to “focus on a target” positioned above their tibia. Main Outcome Measures: T1 brain structural imaging was performed for registration of the functional data. For each condition, 3T functional magnetic resonance imaging blood oxygenation level dependent data representing 90 whole-brain volumes were acquired. Results: During the external relative to internal condition, increased activation was detected in the right occipital pole, cuneal cortex, anterior portion of the lingual gyrus, and intracalcarine cortex (Zmax = 4.5–6.2, P Zmax = 3.4–3.5, P Conclusions: Current results suggest that an external focus directed toward a visual target produces more brain activity in regions associated with vision and ventral streaming pathways, whereas an internal focus manipulated through instruction increases activation in brain regions that are responsible for motor control. Results from this study serve as baseline information for future prevention and rehabilitation investigations of how manipulating focus of attention can constructively affect neuroplasticity during training and rehabilitation.